May Pen, Jamaica -- It's been nearly a year since Sevina Giderisingh's 20-year-old son died in a confrontation with a police officer on the dusty outskirts of this struggling Jamaican city, where jobs are scarce and crime abounds.

The only explanation she's gotten from detectives in gritty May Pen is that an officer shot her eldest son in self-defense one afternoon last June after he was accused of stealing a taxi. But she says a witness told a starkly different story: Her slender son, Alphanso, was unarmed and on his knees begging for his life when he was shot.

"Even if he got involved in something bad, my son had the right to go to court. This killing was a crime, but where's the punishment?" asked a teary-eyed Giderisingh, clutching her son's high school graduation photo.

It's not an uncommon event in Jamaica's poorest neighborhoods, where police and soldiers regularly impose dusk-to-dawn curfews and slum dwellers say security forces behave as if they are at war. Lawmen are routinely accused of shooting indiscriminately, planting pistols next to dead bodies and collecting spent shells.

But in an unprecedented investigation, 27 police officers across the island are facing murder charges brought by a commission created by parliament about four years ago. Eight of the officers are based in a single police division that includes Clarendon parish, where May Pen is the capital.

The Independent Commission of Investigations started work in August 2010, a few months after the bloodiest episode in Jamaica's recent history: More than 70 civilians were killed in a barricaded Kingston slum while security forces hunted the island's gang kingpin during a state of emergency.

After years of wrangling with police, a Jamaican court ruled last year that the commission has the power to arrest and charge officers accused of abuse. Senior commanders of the Jamaica Constabulary Force have long dismissed accusations of unlawful killings and crime scene manipulation as exaggerated, noting that officers work in gang-ridden enclaves awash with illegal firearms. About a dozen officers are killed each year in Jamaica, which the U.N. says has the world's sixth-highest homicide rate.